See this link for Demron, a radiation "proof" fabric. Apparently light weight. Why could this not be incorporated into a/c linings or even the flight deck linings? Blankets for crew rest? That would halve the exposure. $$ I imagine.
http://www.radshieldstore.com/
I fly s/h but had a mate at QF and they were limited to 1 route per month over the poles. This was about 5 years ago.
From other reading I have done the most exposure seems to be in the cockpit, cabin is more safe due to cargo underneath and more metal above.
Thoughts?